Loss of Bcl-2 expression correlates with tumour recurrence in colorectal cancer

Diagnostic and prognostic value of Bcl-2 in uterine leiomyosarcoma

BACKGROUND

Uterine leiomyosarcoma (uLMS) may show loss of expression of B-cell lymphoma-2 (Bcl-2) protein. It has been suggested that Bcl-2 loss may both be a diagnostic marker and an unfavorable prognostic marker in uLMS.

OBJECTIVE

To define the diagnostic and prognostic value of Bcl-2 loss in uLMS through a systematic review and meta-analysis.

METHODS

Electronic databases were searched from their inception to May 2020 for all studies assessing the diagnostic and prognostic value of Bcl-2 loss of immunohistochemical expression in uLMS. Data were extracted to calculate odds ratio (OR) for the association of Bcl-2 with uLMS vs leiomyoma variants and smooth-muscle tumors of uncertain malignant potential (STUMP), and hazard ratio (HR) for overall survival; a p value < 0.05 was considered significant.

RESULTS

Eight studies with 388 patients were included. Loss of Bcl-2 expression in uLMS was not significantly associated with a diagnosis of uLMS vs leiomyoma variants and STUMP (OR = 2.981; p = 0.48). Bcl-2 loss was significantly associated with shorter overall survival in uLMS (HR = 3.722; p = 0.006). High statistical heterogeneity was observed in both analyses.

CONCLUSION

Loss of Bcl-2 expression appears as a significant prognostic but not diagnostic marker in uLMS. The high heterogeneity observed highlights the need for further research and larger studies.

Prognostic value of Bcl2 and Bcl6 in primary cutaneous large B-cell lymphoma: A systematic review and meta-analysis

AIMS

To assess the prognostic value of Bcl2 and Bcl6 in primary cutaneous diffuse large B-cell lymphoma (pcDLBCL), through a systematic review and meta-analysis.

METHODS

Electronic databases were searched from their inception to April 2021 for studies reporting Bcl2 and Bcl6 expression and survival outcomes in pcDLBCL series. Kaplan-Meier and Cox regression survival analyses with hazard ratio calculation were performed for overall survival (OS), with a significant p-value< 0.05.

RESULTS

Eight studies with 148 patients were included. OS was significantly decreased in Bcl2-pos itive pcDLBCLs (5-year OS= 52.9 ± 5.2%) compared to Bcl2 negative pcDLBCLs (5-year OS= 86.6 ± 7.2%), with a HR of 4.615 (95% CI, 1.827-11.657; p = 0.001); no significant difference in OS was found between Bcl6-positive pcDLBCLs (5-year OS= 61.3 ± 6.5%) and Bcl6-negative pcDLBCLs (5-year OS= 56.8 ± 7.2%), with a HR of 0.789 (95% CI, 0.462-1.350; p = 0.388).

CONCLUSIONS

In pcDLBCL, Bcl2 expression is a strong unfavourable prognostic marker; Bcl6 does not seem to be associated with survival instead. Further studies are necessary in this field.

Tiny but Mighty: Collision Tumor of a Superficial Adenocarcinoma Arising From a Tubulovillous Adenoma with Associated Low-Grade Follicular Lymphoma

Collision tumors are rare and there have only been a few previously described cases between an intestinal adenoma and a lymphoma. We report the first case of a 74-year-old woman who on investigation for iron deficiency had a tubulovillous adenoma with underlying follicular lymphoma. The atypical lymphoid proliferation showed immunohistochemical positivity for cluster of differentiation 20 (CD20), B-cell lymphoma 2 (BCL2), and B-cell lymphoma 6 (BCL6). Subsequent right hemicolectomy showed a superficially invasive adenocarcinoma.

Prognostic value of Bcl2 and p53 in Hodgkin lymphoma: A systematic review and meta-analysis

AIMS

Several studies suggested that high expression of Bcl2 and/or p53 in Hodgkin/Reed-Sternberg cells is an unfavorable prognostic factor in Hodgkin lymphoma (HL). However, results in this field appear contrasting. We aimed to assess the prognostic value of p53 and Bcl2 in HL through a systematic review and meta-analysis.

METHODS

Electronic databases were searched from January 2000 to December 2020 for all studies assessing the prognostic value of p53 and Bcl2 in HL. The association of high p53 or Bcl2 expression with overall survival (OS), progression-free survival (PFS) and response to treatment was assessed by using hazard ratio (HR) and odds ratio (OR).

RESULTS

Eighteen studies were included. Bcl2 overexpression was significantly associated with decreased PFS (HR = 2.202; p < 0.0001), while the associations with decreased OS (HR = 1.565; p = 0.257) and refractoriness to treatment (OR = 0.482; p = 0.068) were non-significant. p53 overexpression was not significantly associated with refractoriness to treatment (OR = 0.904; p = 0.155); the analysis of OS and PFS was not feasible, but published data suggested the absence of a significant association.

CONCLUSIONS

In HL, Bcl2 overexpression is associated with decreased PFS, while a significant prognostic value could not be demonstrated for p53. Defining optimal criteria for interpreting Bcl2 and p53 immunostaining is necessary to draw definitive conclusions.

Personalized Medicine-Current and Emerging Predictive and Prognostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide and is heterogeneous both morphologically and molecularly. In an era of personalized medicine, the greatest challenge is to predict individual response to therapy and distinguish patients likely to be cured with surgical resection of tumors and systemic therapy from those resistant or non-responsive to treatment. Patients would avoid futile treatments, including clinical trial regimes and ultimately this would prevent under- and over-treatment and reduce unnecessary adverse side effects. In this review, the potential of specific biomarkers will be explored to address two key questions—1) Can the prognosis of patients that will fare well or poorly be determined beyond currently recognized prognostic indicators? and 2) Can an individual patient’s response to therapy be predicted and those who will most likely benefit from treatment/s be identified? Identifying and validating key prognostic and predictive biomarkers and an understanding of the underlying mechanisms of drug resistance and toxicity in CRC are important steps in order to personalize treatment. This review addresses recent data on biological prognostic and predictive biomarkers in CRC. In addition, patient cohorts most likely to benefit from currently available systemic treatments and/or targeted therapies are discussed in this review.

POFUT1 promotes colorectal cancer development through the activation of Notch1 signaling

Copy number variations (CNVs) are key drivers of colorectal cancer (CRC). Our previous studies revealed that protein O-fucosyltransferase 1 (POFUT1) overexpression is driven by CNVs during CRC development. The potential role and underlying mechanisms of POFUT1 in CRC were not investigated. In this study, we analyzed the expression of POFUT1 in CRC from cosmic and TCGA databases and confirmed that POFUT1 is highly expressed in CRC. We used well characterized CRC cell lines, including SW620 and HCT116 to establish a model POFUT1 knockdown cell line. Using these cells, we investigated the role of POFUT1 in CRC. Our data revealed that silencing POFUT1 in CRC cells inhibits cell proliferation, decreases cell invasion and migration, arrests cell cycle progression, and stimulates CRC cell apoptosis in vitro. We further demonstrate that POFUT1 silencing dramatically suppresses CRC tumor growth and transplantation in vivo. We additionally reveal new mechanistic insights into the role of POFUT1 during CRC, through demonstrating that POFUT1 silencing inhibits Notch1 signaling. Taken together, our findings demonstrate that POFUT1 is a tumor activating gene during CRC development, which positively regulates CRC tumor progression through activating Notch1.

The H1047R point mutation in p110 alpha changes the morphology of human colon HCT116 cancer cells

The class IA phosphatidylinositol 3-kinases (PI3K) is involved in controlling changes in cell morphology, which is a highly coordinated cellular event. This event is powered by actin filament polymerization and remodeling. The gain-of-function mutations in the catalytic subunit of p110α of class IA PI3K, which occur in up to one-third of human colorectal cancers (CRCs), are capable of causing dysregulation of cell signaling and thus may result in the alteration in cell morphology and motility and in turn cause cancer metastasis. In vivo studies have demonstrated that cell lines bearing the H1047R point mutation, the most frequent cancer-specific mutation in the kinase domain of p110α, are more metastatic than cells carrying wild-type p110α. In the current study, we show that the H1047R in p110α of PI3K decreases F-actin polymerization, increases the formation of filopodia and significantly changes the cell morphology in HCT116 cancer cells. The anti-apoptotic protein B-cell lymphoma 2 (Bcl-2), which is also involved in actin polymerization and cell migration, is downregulated by the H1047R mutation in p110α. Our data suggest that the H1047R mutation in PI3K is responsible for the rearrangement of the cytoskeleton, alteration in cell morphology and enhancing cell motility, and that Bcl-2 may be involved in the H1047R mutation-mediated morphological changes and increased migratory capability.

The prognostic value of the apoptosis pathway in colorectal cancer: a review of the literature on biomarkers identified by immunohistochemistry

Research towards biomarkers that predict patient outcome in colorectal cancer (CRC) is rapidly expanding. However, none of these biomarkers have been recommended by the American Association of Clinical Oncology or the European Group on Tumor Markers. Current staging criteria result in substantial under-and over-treatment of CRC patients. Evasion of apoptosis, a characteristic feature of tumorigenesis, is known to correlate with patient outcome. We reviewed the literature on immunohistochemistry-based studies between 1998 and 2011 describing biomarkers in this pathway in CRC and identified 26 markers. Most frequently described were p53, Bcl-2, survivin, and the Fas and TRAILR1 receptors and their ligands. None of the studies reviewed provided sufficient support for implementing a single marker into current clinical practice. This is likely due to the complex biology of this pathway. We suggest focusing on the combination of key markers within the apoptosis pathway that together represent an ‘apoptotic tumor profile’, which better reflects the status of this pathway in a tumor.

Expression Profiling of Proliferation and Apoptotic Markers along the Adenoma-Carcinoma Sequence in Familial Adenomatous Polyposis Patients

Introduction. Familial adenomatous polyposis (FAP) patients have a germline mutation in the adenomatous polyposis coli (APC) gene. The APC protein interacts with beta-catenin, resulting in the activation of the Wnt signalling pathway. This results in alterations in cell proliferation and apoptosis. We investigated the expression of beta-catenin and related proliferation and apoptotic factors in FAP patients, exploring the expression along the adenoma-carcinoma sequence. Methods. The expression of beta-catenin, p53, bcl-2, cyclin-D1, caspase-3, CD10, and Ki-67 proteins was studied by immunohistochemistry in samples of colonic nonneoplastic mucosa (n = 71), adenomas (n = 152), and adenocarcinomas (n = 19) from each of the16 FAP patients. Results. The expression of beta-catenin, caspase-3, cyclin-D1, and Ki-67 was increased in both adenomas and carcinomas in FAP patients, compared with normal mucosa. p53 and CD10 expression was only slightly increased in adenomas, but more frequently expressed in carcinomas. Bcl-2 expression was increased in adenomas, but decreased in carcinomas. Conclusion. This is the first study investigating collectively the expression of these molecules together in nonneoplastic mucosa, adenomas, and carcinomas from FAP patients. We find that beta-catenin and related proliferative and apoptotic factors (cyclin-D1, bcl-2, caspase-3, and Ki-67) are expressed early in the sequence, in adenomas. However, p53 and CD10 are often expressed later in the sequence, in carcinomas.

Comparative proteomic study for profiling differentially expressed proteins between Chinese left- and right-sided colon cancers

The aim of the present study is to profile differentially expressed protein markers between left-sided colon cancer (LSCC) and right-sided colon cancer (RSCC). Fresh tumor tissue samples from LSCC (n = 7) and RSCC (n = 7) groups were analyzed by two-dimensional electrophoresis coupled with MALDI-TOF-MS, followed by Western blotting. In 50 paraffin embedded samples from each group, levels of four differentially expressed proteins (identified by proteomics analysis) were measured by tissue microarray with immunohistochemistry staining to compare the different protein markers between LSCC and RSCC. Sixteen proteins were found to be differentially expressed between LSCC and RSCC. Ten proteins including HSP-60 and PDIA1 were identified to be highly expressed in LSCC (P < 0.01 or P < 0.05), while the expression of six proteins including EEF1D and HSP-27 were higher in RSCC (P < 0.01 or P < 0.05). Virtually all of the indentified proteins were involved in cellular energy metabolism, protein folding/unfolding, and/or oxidative stress. Human colon tumors at various locations have different proteomic biomarkers. Differentially expressed proteins associated with energy metabolism, protein folding/unfolding and oxidative stress contribute to different tumorigenesis, tumor progression, and prognosis between left- and right-sided colon cancer.

Using mice to unveil the genetics of cancer resistance

In the UK, four in ten people will develop some form of cancer during their lifetime, with an individual's relative risk depending on many factors, including age, lifestyle and genetic make-up. Much research has gone into identifying the genes that are mutated in tumorigenesis with the overwhelming majority of genetically-modified (GM) mice in cancer research showing accelerated tumorigenesis or recapitulating key aspects of the tumorigenic process. Yet if six out of ten people will not develop some form of cancer during their lifetime, together with the fact that some cancer patients experience spontaneous regression/remission, it suggests there are ways of 'resisting' cancer. Indeed, there are wildtype, spontaneously-arising mutants and GM mice that show some form of 'resistance' to cancer. Identification of mice with increased resistance to cancer is a novel aspect of cancer research that is important in terms of providing both chemopreventative and therapeutic options. In this review we describe the different mouse lines that display a 'cancer resistance' phenotype and discuss the molecular basis of their resistance.

Development and progression of colorectal neoplasia

A variety of genetic and molecular alterations underlie the development and progression of colorectal neoplasia (CRN). Most of these cancers arise sporadically due to multiple somatic mutations and genetic instability. Genetic instability includes chromosomal instability (CIN) and microsatellite instability (MSI), which is observed in most hereditary non-polyposis colon cancers (HNPCCs) and accounts for a small proportion of sporadic CRN. Although many biomarkers have been used in the diagnosis and prediction of the clinical outcomes of CRNs, no single marker has established value. New markers and genes associated with the development and progression of CRNs are being discovered at an accelerated rate. CRN is a heterogeneous disease, especially with respect to the anatomic location of the tumor, race/ethnicity differences, and genetic and dietary interactions that influence its development and progression and act as confounders. Hence, efforts related to biomarker discovery should focus on identification of individual differences based on tumor stage, tumor anatomic location, and race/ethnicity; on the discovery of molecules (genes, mRNA transcripts, and proteins) relevant to these differences; and on development of therapeutic approaches to target these molecules in developing personalized medicine. Such strategies have the potential of reducing the personal and socio-economic burden of CRNs. Here, we systematically review molecular and other pathologic features as they relate to the development, early detection, diagnosis, prognosis, progression, and prevention of CRNs, especially colorectal cancers (CRCs).

Profiling protein markers associated with the sensitivity to concurrent chemoradiotherapy in human cervical carcinoma

Concurrent chemoradiotherapy (CCRT) is recently recommended as the primary and standard treatment modality for cervical cancer. The aim of this study is to investigate the protein biomarkers associated with CCRT sensitivity, so as to better understand the mechanisms underlying CCRT resistance. Fresh tumor tissues from five cases for each group of CCRT-highly sensitive (CCRT-HS) and CCRT-lowly sensitive (CCRT-LS) were analyzed by 2-D electrophoresis coupled with MALDI-TOF-MS, followed by Western blot for four candidate proteins including S100A9, galectin-7, nuclear matrix protein-238 (NMP-238), and heat shock protein-70 (HSP-70). In randomly selected CCRT-HS (n = 60) and CCRT-LS (n = 35) cases, these four differentially expressed proteins were detected by tissue microarray with immunohistochemistry staining to explore the association between these interested proteins and CCRT sensitivity. Nineteen proteins differentially expressed more than four times between two groups were identified. An association was revealed between CCRT sensitivity and increased S100A9 and galectin-7, but decreased NMP-238 and HSP-70 expression (p < 0.001, respectively). Although none of these four protein markers could be used as an independent predictive factor, a recurrence prediction model was generated by combining S100A9, galectin-7, NMP-238, and HSP-70 as a full predictive factor. The proteomic analysis combined with tissue microarray provides us a dramatic tool in predicting CCRT response. The increased expression of S100A9 and galectin-7, but decreased expression of NMP-238 and HSP-70, suggests a significantly increased sensitivity to CCRT in cervical cancer.

Modulated T-complex protein 1 ζ and peptidyl-prolyl cis-trans isomerase B are two novel indicators for evaluating lymph node metastasis in colorectal cancer: Evidence from proteomics and bioinformatics

Lymph node metastasis (LNM) is an important indicator for systematic therapy, which could increase the survival of colorectal cancer (CRC) patients. However, effective clinical evaluation for LNM is still absent to date. In this study, protein expression profiles of CRC tissues were compared between patients with and without LNM. Based on average expression level, 12 proteins were found to be differentially expressed in the CRC tissues with LNM, whose discrimination reliability was confirmed by PCA. With stepwise linear discriminant analysis, T-complex protein 1 ζ subunit and peptidyl-prolyl cis-trans isomerase B (PPIB) were identified as two main contributors for separating CRC tissues with positive LNM from those negative ones in both original-grouped and cross-validated-grouped cases, which was also supported in subsequent linear support vector machine analysis. In addition, the expression alterations of the two proteins were verified by Western blot and immunohistochemistry. Functional studies also confirmed the role of PPIB in migration and invasion of cancer cells. Taken together, the down-regulated T-complex protein 1 ζ subunit and up-regulated PPIB were identified as two promising indicators for the clinical evaluation of LNM in CRC patients.

Proteome analysis and tissue microarray for profiling protein markers associated with lymph node metastasis in colorectal cancer

BACKGROUND

Understanding the proteins associated with lymph node metastasis (LNM) in colorectal cancer (CRC) will benefit us in the prediction of CRC prognosis and provide us new potential targets in the intervention of CRC. The aim of this study is to investigate the LNM-associated proteins and to evaluate the clinicopathological characteristics of these target proteins' expression in CRC.

METHODS

Fresh tumor and paired normal mucosa from five cases for each group of non-LNM CRC and LNM CRC were analyzed by two-dimensional electrophoresis coupled with MALDI-TOF-MS, followed by Western blotting confirmation. In 40 paraffin-embedded CRC samples, each for non-LNM CRC and LNM CRC, four differentially expressed proteins identified by proteomics analysis were detected by tissue microarray with immunohistochemistry staining to access the clinicopathological characteristics of these proteins in LNM of CRC.

RESULTS

Twenty-five proteins were found to be differentially expressed between normal mucosa and CRC tissue. Increased expression levels of heat shock protein-27 (HSP-27), glutathione S-transferase (GST), and Annexin II, but a decreased expression level of liver-fatty acid binding protein (L-FABP), existed in LNM CRC as compared with non-LNM CRC (p<0.01 or p<0.05, respectively).

CONCLUSION

The techniques of proteomic analysis combined with tissue microarray provide us a dramatic tool for screening of LNM-associated proteins in cancer research. The increased expression of HSP-27, GST, and Annexin II, but decreased expression of L-FABP, suggests a significantly elevated incidence of LNM in CRC.

Recurrence and survival predictive value of phenotypic expression of Bcl-2 varies with tumor stage of colorectal adenocarcinoma

Although decreased or lack of expression of Bcl-2 has been correlated with advanced tumor stage and shortened patient survival in colorectal cancer (CRC), its value in predicting the recurrence has not been well explored. Therefore, we assessed the usefulness of phenotypic expression of Bcl-2 in non-Hispanic Caucasian patients with CRCs in identifying risk of recurrence. Archival tissues of 92 Stage II and 66 Stage III primary CRCs were evaluated for immunohistochemical expression of Bcl-2. None of these patients received either pre- or post-surgical adjuvant therapies. Kaplan-Meier and Cox proportional hazards methods were used to estimate the rates of recurrence and survival according to Bcl-2 expression. Decreased expression of Bcl-2 was associated with an increased rate of recurrence in patients with Stage II CRCs (5-year log-rank test P=0.0015; Hazard Ratio (HR)=3.90, 95%C.I.:1.55-9.77) but not with Stage III CRCs (5-year log-rank test P=0.6058; HR=1.07, 95%C.I.:0.47-2.45) after adjusting for other demographic and clinicopathological features. Furthermore, decreased expression of Bcl-2 was an indicator of short survival in patients with Stage II CRCs but not with Stage III CRCs. Thus, decreased or lack of Bcl-2 expression in primary CRCs may serve as a molecular biomarker of high risk of recurrence for Caucasian patients with Stage II CRCs. These findings might be useful in identifying biologically aggressive phenotypes of Stage II CRCs, and may aid the oncologist in designing maximally appropriate therapeutic regimens.

Bcl-2 expression in rectal cancer

BACKGROUD: Proteins involved in apoptosis process seem to play an important role in colorectal carcinogenesis AIM: To determine the prevalence of bcl-2 protein immunohistochemical expression and its relation with clinical and histopathological variables of rectal adenocarcinoma. PATIENTS AND METHODS: One hundred and thirty-two patients operated at "Hospital de Clínicas de Porto Alegre", Porto Alegre, RS, Brazil, between 1988 and 1999 were studied through immunohistochemical reaction using a monoclonal antibody anti-bcl-2 on formalin-fixed, paraffin-embedded tissue samples RESULTS: The prevalence of bcl-2 protein was 29.5%. There was a significant increased number of positive bcl-2 cases among women as compared to men. There was no significant association between bcl-2 and age, tumour site, histological grade, mucin production, depth of invasion, lymphatic involvement, distant metastasis or stage, despite a trend showing decreased immunoreactivity to bcl-2 among poorly and moderately differentiated tumours, as well as disseminated disease CONCLUSIONS: Analysis of bcl-2 protein expression in tumour tissues, as well as other oncoproteins, may have a role in predict therapeutic response and prognosis of colorectal cancer. However, the potential use of bcl-2 protein assessment in the clinical set for management of rectal cancer remains to be determined.

Differential expression of Bcl-2, Bcl-XL and p53 in colorectal cancer

AIMS

The balance between proliferation and apoptosis is often disturbed in cancer. The aim of this study was to investigate the possible role of Bcl-2 gene family members and p53 as prognostic factors in a series of colorectal cancer.

METHODS

The immunohistochemical expression of Bcl-2 gene family members (Bcl-2 and Bcl-X(L)) and p53 was evaluated in 81 surgical specimens of primary human colorectal cancers to establish the role of these genes in colorectal cancer and to evaluate their prognostic importance.

RESULTS

The expression of Bcl-2 correlated with early clinical stage and lack of lymphovascular invasion and lymph node involvement. The expression of p53 correlated with less differentiated status and with perineural invasion. p53 expression showed negative correlation with Bcl-X(L) expression (P = 0.025) and no correlation with Bcl-2 expression.

CONCLUSIONS

p53 expression may be a less favorable marker and Bcl-2 expression a more favorable marker of behavior. Bcl-2 and Bcl-X(L) may play an independent role in disease progression, and the expression of these proteins may be under independent regulatory control in colorectal cancer.

Association between Bcl-2 expression and tumor recurrence in cervical cancer: a matched case-control study

OBJECTIVES

To evaluate the association between bcl-2 expression, some pathological factors (lymph-vascular space invasion (LVSI), tumor grade, depth of stromal invasion), and tumor recurrence in cervical cancer.

METHODS

A matched case-control study was performed in cervical cancer patients who underwent radical hysterectomy and were found to have negative lymph node between January 1992 and June 1998 in Bangkok Metropolitan Administration Medical College and Vajira Hospital and Maharaj Nakorn Chiangmai Hospital, Thailand. Cases were 32 patients who had tumor recurrence within 5 years after surgery. Controls were 63 patients who were disease free for at least 5 years after surgery. Cases and controls were matched for age, stage, histology, and tumor size. All except one case, who had only one matching control, had two controls. Paraffin-embedded cervical cancer tissues of cases and controls were immunohistochemical stained for bcl-2.

RESULTS

Bcl-2 positive was demonstrated in 43.7% of tumor from recurrent cases, which was not different from 50.8% from non-recurrent controls (P = 0.378). Tumor grade and LVSI had significant association with tumor recurrence. From multivariable analysis, the patients with grade 2-3 tumors had the odds ratio of 6.9 for recurrence compared to patients with grade 1 tumors. The patients whose tumors had LVSI had the recurrent odds ratio of 5.4 compared to those without LVSI.

CONCLUSIONS

There was no association between bcl-2 expression and tumor recurrence in cervical cancer, while tumor grade and LVSI had significant association with tumor recurrence.

[Current status of the prognostic value of molecular markers in patients with colorectal cancer and the prediction of response to adjuvant therapy]

Colorectal cancer is one of the best studied of all malignant diseases in terms of genetics and/or molecular prognostic factors. These factors, and relationships with prognosis, may have important implications especially in the design of surgical and adjuvant chemo-radiotherapy options. However, the true prognostic significance of all known factors has yet to be realised. We have reviewed the literature with specific focus on the role of molecular markers involved in prognosis and the prediction of response to adjuvant treatment.

Paradoxes of Non-Trivial Gene Networks: How Cancer-Causing Mutations Can Appear to Be Cancer-Protective

Abnormalities of gene structure or expression are commonly found in cancers, where they are used as prognostic markers, predicting the likely severity of disease or chances of response to therapy. An odds ratio (OR) of <1 indicates that a marker's presence is correlated with better outcome. An OR of <1 is also often taken to mean that the gene concerned has a protective effect in the mechanism of cancer. I show that this is not necessarily so. Modeling of the genes involved in the causation of cancer as a network of weak, failure-prone elements shows that "cancer-causing" genes (i.e., genes whose abnormality is causal in driving cancer) can nevertheless appear as "protective" markers in later stage cancers. This implies that results suggesting that well-known oncogenes have an OR of <1 are quite valid, and that predicting a "protective" role from an apparently protective prognostic value is not valid. I identify mdm-2 and bax as candidates for genes with an apparently protective role through this mechanism.

Molecular lesions in colorectal cancer: impact on prognosis? Original data and review of the literature

BACKGROUND

In the Dukes' B and C stages of colorectal carcinoma there are considerable variations in the observed courses of the disease. Since post-operative chemotherapy in patients with Dukes' C (node-positive) colon carcinoma has been demonstrated to be effective in improving overall-survival, a more exact prognosis assessment gains additional significance and therapeutic relevance.

DISCUSSION

One also hopes to derive improved prognostic factors from the clarification of the molecular pathogenesis. Because of its frequency and the accessibility and recognizability of its developmental stages colorectal carcinoma is among the best investigated of all solid tumors. Despite a multitude of suggested molecular candidate markers none of these changes has yet been able enter the everyday life of the clinic. However, it is to be expected that some of the molecular alterations presently discussed will gain importance before long in the clinical treatment of patients with colorectal carcinoma.

CONCLUSION

Considering also our own findings, this review presents the latest developments in the scientific discussion of the tumor suppressor/oncogenes p53, k-ras, and DCC, biochemical determinants of the 5-fluorouracil metabolism, and defects of the DNA repair system.

Prognostic significance and correlation with survival of bcl-2 and TGF-beta RII in colon cancer

Bcl-2 and TGF-beta receptors type II (RII) in colon carcinomas were studied in a series of 113 patients, to determine their prognostic significance and to correlate their expression with other prognostic indicators. Bcl-2 expression in the tumor cells showed a reverse relation with tumor size (P = 0.018), histological grade (P = 0.04), and stage (P = 0.013). Univariate survival analysis using the log rank test showed that the survival of patients with bcl-2-positive tumors was significantly better than the survival of patients with bcl-2-negative tumors (P = 0.02). However, when entered into a multivariate analysis model, it was not found to be of independent prognostic significance. TGF-beta RII expression was correlated with stage (P = 0.03), while no statistically significant correlation was found between TGF-beta RII expression and histological grade or survival. In conclusion, these results provide additional evidence for the role of bcl-2 and TGF-beta RII in carcinogenesis of the colon, while they do not support the use of these factors as prognostic markers in patients with colon cancer.

Recent advances in the development of anticancer agents targeting cell death inhibitors in the Bcl-2 protein family

Hematopoietic malignancies frequently are characterized by defects in apoptosis signaling. This renders the malignant cells resistant to endogenous apoptotic stimuli, as well as exogenous stimuli, such as chemotherapy drugs and radiation. The defective apoptosis seen in human cancers often results from overexpression of antiapoptotic proteins in the Bcl-2 protein family, particularly Bcl-2 and Bcl-X(L). A great deal of effort is currently aimed at developing novel agents to inhibit the expression or function of these proteins. Antisense agents directed against Bcl-2 mRNA are showing considerable promise in clinical trials. In addition, detailed knowledge of the structures of Bcl-2 and Bcl-X(L), coupled with high-throughput and computer-assisted screening of chemical libraries, has led to the identification of a number of short peptides and small organic molecules capable of inhibiting Bcl-2 and Bcl-X(L) function. These newly described agents hold considerable promise for enhancing the chemo- and radiation sensitivities of Bcl-2- and Bcl-X(L)-overexpressing cancers. This review will highlight recent advances in the development and testing of agents targeting cell death inhibitors in the Bcl-2 protein family.

Effect of yogurt on the inhibition of an intestinal carcinoma by increasing cellular apoptosis

Yogurt consumption has been associated with decreased risk of colon cancer. The apoptosis induced by yogurt as a mechanism involved in the inhibition of an experimental intestinal tumor induced by 1,2 dimethylhydrazine (DMH) in BALB/c mice, has been studied. An imbalance between apoptosis and mitosis or cell proliferation is believed to underlie colon cancer development and progression. We determined the effect of yogurt feeding in the induction of apoptosis and the relationship between mitosis and apoptosis in mice injected with the carcinogen DMH and in mice injected with DMH and fed with a diet supplemented with yogurt. The percentage of mitotic and apoptotic cells was analyzed every 2 weeks from week 8 to 16. They were analyzed on histological slices from the large intestine by colchicine, or Tunel test for mitosis and apoptosis determination, respectively. An increase in the mitosis during the first 4 weeks of tumor development with apoptosis negative and severe dysphasia, was observed in animals treated with the carcinogen. In those animals that received DMH and were given yogurt, a moderate cell proliferation with a significant increase in the number of apoptotic cells was determined. The increase in the apoptotic activity was also observed in the group of animals that received only a diet supplemented with yogurt. The results suggest that yogurt would influence the balance between mitosis and apoptosis, which was modified during the carcinogenesis process, by increasing cellular apoptosis. Dietary supplementation of yogurt may play a role in modulating cell proliferation or apoptosis during the development of colorectal carcinoma.

Molecular staging of colorectal cancer in African-American and Caucasian patients using phenotypic expression of p53, Bcl-2, MUC-1 AND p27(kip-1)

The gold standard for clinical outcome of most cancers has been the clinical and pathologic staging of the tumors after surgery. For colorectal cancer (CRC), nodal involvement at the time the primary tumor is resected has been the most reliable indicator of clinical outcome; however, recently, combinations of molecular markers have been reported to be equivalent to pathologic or clinical staging in predicting clinical outcome. In addition, molecular markers can be used in conjunction with clinical or pathologic staging to provide a stronger indicator of clinical outcome than staging alone. We propose that "molecular staging" be added to pathologic staging to aid in predicting clinical outcome and making therapeutic decisions for colorectal cancers, especially stage II and III CRCs. We have reported that the clinical usefulness of most molecular markers varies with the ethnic group of the patients and the anatomic location of CRCs; this complicates the evaluation of prognostic biomarkers and requires much larger numbers of cases to be evaluated. Nevertheless, nuclear accumulation of p53 (p53(nac)) and phenotypic expression of Bcl-2, MUC-1 and p27(kip-1) may be molecular markers approaching acceptance for use in molecular staging of specific subgroups of colorectal cancers.

The results of colorectal cancer treatment by p53 status: treatment-specific overview

PURPOSE

Both negative and positive influences of mutant p53 on treatment outcome have been reported, and we present here a meta-analysis of published studies where outcome was reported for defined treatment groups.

METHODS

We identified articles on the effect of p53 status by treatment modality, excluding those not stratified by method of treatment. A common hazard ratio was estimated from studies that reported a multivariate analysis. We also estimated the numbers of patients expressing the endpoint at the mean or median follow-up time and calculated a pooled odds ratio.

RESULTS

Twenty-eight articles were evaluable (23 using immunohistochemistry to detect overexpression of p53 and 8 using DNA sequencing), for a total of 4,416 patients. For patients treated with surgery only, the immunohistochemistry studies showed a significant influence of p53 status on disease-free survival and a marginally significant influence on overall survival. In the studies using DNA sequencing, by contrast, there was a significant influence of p53 mutations on overall survival, but not disease-free survival. For patients treated with surgery and radiotherapy, the influence of p53 status on disease-free survival was either insignificant or marginally significant, depending on test used; there was no influence on overall survival.

CONCLUSIONS

Although this pooled analysis of published studies where treatment was accounted for shows that there is a borderline significant hazard associated with p53 overexpression or mutation vs. p53 wild-type, it is unlikely that p53 can be applied in a routine clinical setting alongside factors such as T stage, nodal status, and residual tumor, whose prognostic value is much stronger.

Bcl-2 expression is associated with improved prognosis in patients with distal colorectal adenocarcinomas

Several recent studies have suggested that the anatomic location of the tumor and ethnicity of the patient should be considered in the evaluation of prognostic markers of colorectal neoplasia. The phenotypic expression of Bcl-2 has been reported to be a useful prognostic marker in colorectal adenocarcinoma (CRC). However, its prognostic importance in CRCs based on their anatomic location and on the ethnicity of the patients has not been reported. Therefore, we evaluated Bcl-2 expression by immunohistochemistry in CRCs collected from 107 African-American and 149 Caucasian patients from a southern U.S. population. In univariate Kaplan-Meier survival analyses, Bcl-2 expression was associated with better overall survival of both African-American (log-rank, p = 0.040) and Caucasian (log-rank, p = 0.032) patients with distal but not with proximal CRCs. In multivariate Cox regression analyses, when the pathologic features of tumors were not included, the expression of Bcl-2 was associated with better survival in either ethnic patient populations with distal CRCs after adjusting for other confounding variables and p53(nac) status; however, it was not significant in either race when tumor stage was included in multivariate analyses. Thus, these studies suggest that the expression of Bcl-2 in CRCs is a valuable indicator of good prognosis in either race when CRCs are located in the distal colorectum. Also, these studies suggest that the expression of Bcl-2 is useful in determining prognosis before pathologic-clinical staging and it can aid in selection of treatment after evaluation of diagnostic biopsy specimens of patients with distal colorectal adenocarcinomas.

p53 and Bcl-2 as significant predictors of recurrence and survival in rectal cancer

The aim of this study was to evaluate the prognostic value of p53 nuclear accumulation and Bcl-2 expression after curative surgery for rectal cancer. Immunohistochemistry was performed using monoclonal antibodies (MAb) (DO-1 for p53; anti-human Bcl-2 MAb, clone 124, for Bcl-2) on formalin-fixed, paraffin-embedded tissues of 160 rectal carcinomas (UICC stages I-III), and results were compared with data from the prospective registry of rectal cancer by univariate and multivariate logistic regression model focusing specifically on recurrence. Survival was calculated by the Kaplan-Meier method and proportional hazards model. p53 nuclear accumulation was documented in 39% (n=63) of tumours and was associated with a higher incidence of tumour progression (local or distant recurrence) and poorer disease-free survival (P<0.0001). Bcl-2 expression was detected in 29% (n=47), and was associated with longer disease-free survival and lower incidence of recurrence (P<0.0086). Multivariate logistic regression analysis demonstrated that gender (P=0.0136), UICC stage (P=0.0002), p53 expression (P=0.0002) and Bcl-2 expression (P=0. 0243) were independent factors predictive of recurrence. The proportional hazards model identified p53 (P=0.0009), UICC stage (P=0.0480), gender (P=0.0049), but not Bcl-2 (P=0.1503), as independently related to disease-free survival. Looking at the p53/Bcl-2 subgroups, the poorest prognosis was observed in the p53+/Bcl-2- subgroup, whereas patients whose tumours were p53-/Bcl-2+ had the best prognosis (P<0.0001). Immunohistochemical assessment of both p53 and Bcl-2 status may be valuable in predicting recurrence and survival after curative surgery for rectal cancer. Therefore, they play a role as prognostic factors in rectal cancer. p53 is a stronger predictor of prognosis than Bcl-2.

Topographic distribution of bcl-2 protein in feline tissues in health and neoplasia

The bcl-2 family of genes encodes proteins that influence apoptosis. In the present immunohistochemical study, the topographic distribution of bcl-2 protein was examined in healthy feline fetal, neonatal, and adult tissues, a feline renal cell line, and feline tumors obtained from a veterinary hospital. The topographic distribution of bcl-2 in healthy tissues was similar to that described in human tissues. In lymphoid tissues, follicular mantle cells strongly expressed bcl-2. In complex and differentiating epithelium, bcl-2 expression was detected in stem cell and proliferation zones. Bcl-2 expression was also detected in lower crypts of the intestine and in skin basal layers. The feline Crandell kidney cells expressed bcl-2 diffusely throughout the cytoplasm. Of 180 tumors examined, bcl-2 was expressed almost uniformly in cutaneous basal cell tumors, thyroid adenomas, and mammary carcinomas and in 50% of the lymphomas examined. Bcl-2 may play a role in blocking apoptotic cell death in a broad range of normal feline tissues, whereas dysregulated bcl-2 may extend the life of certain tumors or render certain tumors resistant to therapy because most chemotherapeutic and radiotherapeutic agents eliminate tumor cells by triggering apoptosis.

bcl-2 protein expression is associated with better prognosis in colorectal cancer

AIMS

To investigate the expression of bcl-2 in colorectal carcinoma and to examine its association with mediators of apoptosis (p53 and mdm-2), clinicopathological features and long-term outcome.

METHODS AND RESULTS

We determined by immunohistochemistry the expression of bcl-2 in 102 colorectal carcinomas with 10-year follow-up. In 66 of these cases in which we had previously assessed p53 status, no correlation was seen between bcl-2 and p53. The mdm-2 protein was not detected in any of the 66 cases. Cytoplasmic staining of the bcl-2 gene product was seen in the tumour cells of 22 cases (22%). Using a polymerase chain reaction technique we showed that overexpression of bcl-2 was not due to rearrangement of the bcl-2 gene. Expression of bcl-2 protein was related to tumour grade but was unrelated to patient age, sex, tumour site, tumour size or Dukes' stage. There was a trend towards increased survival in those whose tumours expressed bcl-2 protein (P = 0.055). When entered into a multivariate analysis, this survival difference was independent of tumour stage (P = 0.05).

CONCLUSIONS

These results suggest that bcl-2 expression in colorectal carcinoma is associated with a better long-term prognosis.

Tumor markers--prognostic and therapeutic implications for colorectal carcinoma

Molecular prognostic markers are molecules produced by either the tumor or the host (patient) whose expression is associated with the clinical outcome. Three types of molecular markers exist that characterize different aspects of the tumor : host relationship: (1) tumor biology, (2) tumor burden and (3) host response. The first type of marker is measured within the primary or metastatic tumor mass and defines the aggressiveness of the cancer and its ability to respond to therapy. The other two types of markers are usually measured in the blood and assess concentrations of circulating tumor products or cytokines that may be involved in host resistance to the cancer. In this brief review we will define each type of marker, provide examples of their current utility and then describe how these markers may be useful.